Method and system for vacuum generation using a throttle comprising a hollow passage

ABSTRACT

Various systems and methods are described for generating vacuum within an engine intake. A system may comprise an intake throttle including a throttle plate, where the throttle plate may comprise a hollow interior passage, which in turn may be coupled to a vacuum consumption device. When vacuum is demanded by the vacuum consumption device, the throttle plate may be adjusted to increase airflow through the interior passage and vacuum may be generated at a constricted portion of the interior passage by flowing intake air through the interior passage of the throttle plate.

TECHNICAL FIELD

The present application relates to vacuum generation in an intake via athrottle plate.

BACKGROUND AND SUMMARY

Vehicle systems may include various vacuum consumption devices that areactuated using vacuum. These may include, for example, a brake boosterand a purge canister. Vacuum used by these devices may be provided by adedicated vacuum pump. In other embodiments, one or more aspirators(alternatively referred to as ejectors, venturi pumps, jet pumps, andeductors) may be coupled in the engine system that may harness engineairflow and use it to generate vacuum.

In yet another example embodiment shown by Bergbauer et al. in U.S. Pat.No. 8,261,716, a control bore is located in the wall of the intake suchthat when the throttle plate is at idle position, vacuum generated atthe periphery of the throttle is used for a vacuum consumption device.Therein, the positioning of the throttle plate in an idle positionprovides a constriction at the throttle plate's periphery. Theincreasing flow of intake air through the constriction results in aventuri effect that generates a partial vacuum. The control bore issited so as to utilize the partial vacuum for a vacuum consumptiondevice.

However in the approaches described above, the vacuum generationpotential of the throttle is limited. For example, a single control boreat one location in the intake, as shown in U.S. Pat. No. 8,261,716, isutilized by the vacuum consumption device even though vacuum may begenerated at the entire periphery of the throttle. To use vacuumgenerated at the entire periphery of the throttle, more control boresmay be needed in the intake passage. However, fabricating these controlbores may result in significant modifications to the design of theintake passage which can increase related expenses.

In the approaches that use one or more aspirators to generate vacuum,additional expenses may be incurred because of individual parts thatform the aspirator including nozzles, mixing and diffusion sections, andcheck valves. Further, at idle or low load conditions, it may bedifficult to control the total air flow rate into the intake manifoldsince the flow rate is a combination of leakage flow from the throttleand airflow from the aspirator. Typically, an aspirator shut off valve(ASOV) may be included along with the aspirator to control airflow butwith added cost. Further, installing aspirators in the intake can leadto constraints on space availability as well as packaging issues.

As such, some approaches so address the above issues include providing aplurality of perforations around a circumference of a hollow intakethrottle plate. The throttle plate may be adjusted to a more closedposition to generate vacuum via intake airflow past the perforations onthe circumference of the throttle plate. The generated vacuum is thenapplied to a vacuum consumption device fluidly coupled to the throttleplate via a hollow shaft.

The inventors herein have identified potential issues with the aboveapproach. As an example, the vacuum generation potential of the throttleis limited. As an example, the size of the perforations may be limiteddue to the width of the throttle plate, and therefore the vacuumgeneration potential of the throttle is limited. Thus, in order toincrease the vacuum generated at the periphery of the throttle, the sizeof the perforations may need to be increased. However, increasing thesize of the perforations may result in increases of the size and of thethrottle which may result in significant modifications to the design ofthe intake passage which can increase related expenses.

The inventors herein have identified an approach to at least partlyaddress the above issues. In one example approach, a method may compriseadjusting a position of a throttle plate with a hollow interior passage,and generating vacuum at a constricted portion of the interior passage,via intake airflow through the interior passage of the throttle plate.In this way, the throttle plate can function as an aspirator and supplyvacuum to the vacuum consumption device. Further the vacuum generationpotential of the throttle plate may be adjusted by adjusted one or moreof the position of the throttle plate, and the size of the hollowinterior passage in the throttle plate.

As an example, an engine intake throttle may be configured as a throttleplate mounted on a hollow shaft. The hollow shaft may fluidically couplethe hollow interior passage of the throttle plate to a vacuumconsumption device. When the vacuum demand of the vacuum consumptiondevice coupled to the throttle plate increases, the throttle plate maybe adjusted to a more closed position. As a result, vacuum may begenerated by the flow of intake air through a constricted portion of theinterior passage of the throttle. This vacuum may be applied to thevacuum consumption device by flowing air from the vacuum consumptiondevice through the hollow shaft into the interior passage of thethrottle plate and thereon, into intake airflow that flows through theinterior passage. Once sufficient vacuum has been generated, thethrottle position may be returned to a more open position.

In this way, a venturi flow passage created at a constricted portion ofthe interior passage can be advantageously used to generate vacuum for avacuum consumption device. The constricted portion of the interiorpassage can be used to provide a channel to draw air or gas from thevacuum consumption device via the hollow shaft. By adjusting thelocation and size of the interior passage, the vacuum generationpotential of the throttle plate may be increased. In addition, airflowinto the intake manifold can be better controlled by adjusting thedistance between the inside of the intake passage and the edge of thethrottle plate. Furthermore, since air received from the vacuumconsumption device during vacuum application is received substantiallyat the throttle plate, airflow errors can be better compensated for. Bycombining the functions of a throttle and an aspirator into a singlethrottle plate with a hollow interior passage, additional controlvalves, such as an ASOV, and parts may not be needed. Further, thevacuum generation ability of the throttle is improved without requiringsignificant modifications to the intake passage. By reducing the numberand size of components required for vacuum generation, manufacturingexpenses may be lowered and packaging issues may be averted.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 portrays a schematic diagram of an engine in accordance with thepresent disclosure.

FIG. 2A depicts an example embodiment of an intake throttle plate with ahollow interior passage.

FIG. 2B depicts another example embodiment of the intake throttle platefrom FIG. 2A with a hollow interior passage.

FIG. 3 shows a cross sectional view of the throttle plate of FIGS. 2Aand 2B within the intake passage.

FIG. 4A shows a cross sectional view of the throttle plate in a closedfirst position.

FIG. 4B shows a cross sectional view of the throttle plate in anintermediate second position.

FIG. 4C shows a cross sectional view of the throttle plate in anintermediate third position.

FIG. 4D shows a cross sectional view of the throttle plate in an openfourth position.

FIG. 5 shows a schematic illustration of the throttle plate within theintake passage.

FIG. 6 shows a cross-section of the intake passage of FIG. 5 to depictan alternate view of the throttle plate.

FIG. 7 is a flowchart illustrating an example method for adjustingthrottle position and engine operating parameters.

FIG. 8 portrays an example throttle position adjustment to improvevacuum generation with concurrent engine operating parameter adjustmentsto maintain engine torque, according to the present disclosure.

DETAILED DESCRIPTION

Methods and systems are described for generating vacuum within an intakepassage in an engine, such as the engine system shown in FIG. 1. Theintake passage may be provided with an intake throttle comprising athrottle plate with a hollow interior passage coupled to a vacuumconsumption device via a hollow shaft, as shown in FIGS. 2-5.Specifically, the hollow interior passage may extend through the intakethrottle plate from an upstream surface to a downstream surface of thethrottle plate. As such, intake air may flow through the interiorpassage of the throttle plate en route to an intake valve of an enginecylinder. The interior passage may comprise a constricted portion.Specifically, the interior passage may narrow at the constrictedportion, and therefore may a generate vacuum at the constricted portionvia a venturi effect as intake air flows through the constricted portionof the interior passage, as shown in FIGS. 2-5. Vacuum generated at theconstricted portion of the interior passage may be used to draw air fromthe vacuum consumption device. Further, the amount of vacuum generatedat the constricted portion of the interior passage may depend on theamount of airflow through the passage, and therefore may be adjusted byadjusting the position of the throttle plate. A controller may beconfigured to perform a routine to modify a throttle position based onvacuum demand from the vacuum consumption device as shown in FIG. 7. Asshown in FIG. 6, the controller may send signals to an actuator whichmay in turn adjust the position of the throttle plate based on signalsreceived from the controller. Various operating parameters may beadjusted as shown in FIG. 8, as throttle position is varied, to maintainengine torque.

Referring now to FIG. 1, it shows a schematic depiction of a sparkignition internal combustion engine 10. Engine 10 may be controlled atleast partially by a control system including controller 12 and by inputfrom a vehicle operator 132 via an input device 130. In this example,input device 130 includes an accelerator pedal and a pedal positionsensor 134 for generating a proportional pedal position signal PP.

Combustion chamber 30 (also known as, cylinder 30) of engine 10 mayinclude combustion chamber walls 32 with piston 36 positioned therein.Piston 36 may be coupled to crankshaft 40 so that reciprocating motionof the piston is translated into rotational motion of the crankshaft.Crankshaft 40 may be coupled to at least one drive wheel of a vehiclevia an intermediate transmission system (not shown). Further, a startermotor may be coupled to crankshaft 40 via a flywheel (not shown) toenable a starting operation of engine 10.

Combustion chamber 30 may receive intake air from intake manifold 44 viaintake passage 42 and may exhaust combustion gases via exhaust passage48. Intake manifold 44 and exhaust passage 48 can selectivelycommunicate with combustion chamber 30 via respective intake valve 52and exhaust valve 54. In some embodiments, combustion chamber 30 mayinclude two or more intake valves and/or two or more exhaust valves.

In this example, intake valve 52 and exhaust valves 54 may be controlledby cam actuation via respective cam actuation systems 51 and 53. Camactuation systems 51 and 53 may each include one or more cams and mayutilize one or more of cam profile switching (CPS), variable cam timing(VCT), variable valve timing (VVT) and/or variable valve lift (VVL)systems that may be operated by controller 12 to vary valve operation.The position of intake valve 52 and exhaust valve 54 may be determinedby position sensors 55 and 57, respectively. In alternative embodiments,intake valve 52 and/or exhaust valve 54 may be controlled by electricvalve actuation. For example, cylinder 30 may alternatively include anintake valve controlled via electric valve actuation and an exhaustvalve controlled via cam actuation including CPS and/or VCT systems.

Fuel injector 66 is shown coupled directly to combustion chamber 30 forinjecting fuel directly therein in proportion to the pulse width ofsignal FPW received from controller 12 via electronic driver 96. In thismanner, fuel injector 66 provides what is known as direct injection offuel into combustion chamber 30. The fuel injector may be mounted in theside of the combustion chamber or in the top of the combustion chamber,for example. Fuel may be delivered to fuel injector 66 by a fuel system(not shown) including a fuel tank, a fuel pump, and a fuel rail. In someembodiments, combustion chamber 30 may alternatively or additionallyinclude a fuel injector arranged in intake manifold 44 in aconfiguration that provides what is known as port injection of fuel intothe intake port upstream of combustion chamber 30.

Ignition system 88 can provide an ignition spark to combustion chamber30 via spark plug 92 in response to spark advance signal SA fromcontroller 12, under select operating modes. Though spark ignitioncomponents are shown, in some embodiments, combustion chamber 30 or oneor more other combustion chambers of engine 10 may be operated in acompression ignition mode, with or without an ignition spark.

Engine 10 may further include a compression device such as aturbocharger or supercharger including at least a compressor 162arranged along intake passage 42. For a turbocharger, compressor 162 maybe at least partially driven by a turbine 164 (e.g., via a shaft)arranged along exhaust passage 48. Compressor 162 draws air from intakepassage 42 to supply boost chamber 46. Exhaust gases spin turbine 164which is coupled to compressor 162 via shaft 161. For a supercharger,compressor 162 may be at least partially driven by the engine and/or anelectric machine, and may not include a turbine. Thus, the amount ofcompression provided to one or more cylinders of the engine via aturbocharger or supercharger may be varied by controller 12.

A wastegate 168 may be coupled across turbine 164 in a turbocharger.Specifically, wastegate 168 may be included in a bypass 166 coupledbetween an inlet and outlet of the exhaust turbine 164. By adjusting aposition of wastegate 168, an amount of boost provided by the turbinemay be controlled.

Intake manifold 44 is shown communicating with throttle 62 having athrottle plate 64. In this particular example, the position of throttleplate 64 may be varied by controller 12 via a signal provided to anelectric motor or actuator (not shown in FIG. 1) included with throttle62, a configuration that is commonly referred to as electronic throttlecontrol (ETC). Throttle position may be varied by the electric motor viaa shaft. As elaborated at FIG. 2-4, throttle plate 64 may include anopening 68 which fluidically couples the throttle with vacuumconsumption device 140. Throttle 62 may control airflow from intakeboost chamber 46 to intake manifold 44 and combustion chamber 30 amongother engine cylinders. The position of throttle plate 64 may beprovided to controller 12 by throttle position signal TP from throttleposition sensor 58. As such, the position of the throttle plate 64 maybe adjusted by the electric motor based on signals received from thecontroller 12. Said another way, the controller 12 may send signals tothe electric motor for adjusting the position of the throttle plate 64.

Engine 10 is coupled to vacuum consumption device 140 which may include,as non-limiting examples, one of a brake booster, a fuel vapor canister,and a vacuum-actuated valve (such as a vacuum-actuated wastegate).Vacuum consumption device 140 may receive vacuum from a plurality ofvacuum sources. One source may be vacuum pump 77 that may be selectivelyoperated via a control signal from controller 12 to supply vacuum tovacuum consumption device 140. Check valve 69 allows air to flow tovacuum pump 77 from vacuum consumption device 140 and limits airflow tovacuum consumption device 140 from vacuum pump 77. Another source ofvacuum may be throttle plate 64 which is positioned within boost chamber46. Throttle plate 64 has a hollow interior passage 72. As shown in FIG.1, an opening 68 within throttle plate 64 may be connected to vacuumconsumption device 140 via a hollow shaft mounted on bearings (notshown) and coupled to a conduit 198. When throttle plate 64 is in amostly closed or a fully closed position, vacuum may be generated at theinterior passage 72 of throttle plate 64 as intake air flows through theinterior passage 72. This vacuum may draw air from vacuum consumptiondevice 140 through conduit 198, via the hollow shaft into the interiorpassage 72 of the throttle plate 64. This air may then flow out ofthrottle plate 64 via an opening formed at a downstream surface of thethrottle plate 64 and the interior passage 72. Check valve 73 ensuresthat air flows from vacuum consumption device 140 to throttle plate 64and thereon into intake manifold 44 and not from intake manifold 44 tovacuum consumption device 140.

Exhaust gas sensor 126 is shown coupled to exhaust passage 48 upstreamof emission control device 70. Sensor 126 may be any suitable sensor forproviding an indication of exhaust gas air/fuel ratio such as a linearoxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), atwo-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or COsensor. Emission control device 70 is shown arranged along exhaustpassage 48 downstream of exhaust gas sensor 126. Device 70 may be athree way catalyst (TWC), NOx trap, various other emission controldevices, or combinations thereof.

An exhaust gas recirculation (EGR) system may be used to route a desiredportion of exhaust gas from exhaust passage 48 to intake manifold 44through conduit 152 via EGR valve 158. Alternatively, a portion ofcombustion gases may be retained in the combustion chambers, as internalEGR, by controlling the timing of exhaust and intake valves.

Controller 12 is shown in FIG. 1 as a conventional microcomputerincluding: microprocessor unit 102, input/output ports 104, read-onlymemory 106, random access memory 108, keep alive memory 110, and aconventional data bus. Controller 12 commands various actuators such asthrottle plate 64, EGR valve 158 and the like. Controller 12 is shownreceiving various signals from sensors coupled to engine 10, in additionto those signals previously discussed, including: engine coolanttemperature (ECT) from temperature sensor 112 coupled to cooling sleeve114; a position sensor 134 coupled to an accelerator pedal 130 forsensing accelerator position adjusted by vehicle operator 132; ameasurement of engine manifold pressure (MAP) from pressure sensor 121coupled to intake manifold 44; a measurement of boost pressure frompressure sensor 122 coupled to boost chamber 46; a measurement of vacuumin vacuum consumption device 140 from pressure sensor 125, a profileignition pickup signal (PIP) from Hall effect sensor 118 (or other type)coupled to crankshaft 40; a measurement of air mass entering the enginefrom mass airflow sensor 120; and a measurement of throttle positionfrom sensor 58. Barometric pressure may also be sensed (sensor notshown) for processing by controller 12. In a preferred aspect of thepresent description, engine position sensor 118 produces a predeterminednumber of equally spaced pulses every revolution of the crankshaft fromwhich engine speed (RPM) can be determined.

As described above, FIG. 1 merely shows one cylinder of a multi-cylinderengine, and that each cylinder has its own set of intake/exhaust valves,fuel injectors, spark plugs, etc. Also, in the example embodimentsdescribed herein, the engine may be coupled to a starter motor (notshown) for starting the engine. The starter motor may be powered whenthe driver turns a key in the ignition switch on the steering column,for example. The starter is disengaged after engine start, for example,by engine 10 reaching a predetermined speed after a predetermined time.

FIGS. 2A and 2B illustrate schematic diagrams of embodiments 200 and 250respectively, of a throttle plate, coupled to a vacuum consumptiondevice that may be included in the intake of engine 10 of FIG. 1. Assuch, components previously introduced in FIG. 1 are numbered similarlyin FIG. 2 and may not be reintroduced.

FIG. 2A shows a side perspective view of throttle plate 64 positionedwithin boost chamber 46. FIG. 2B shows the same side perspective view ofthrottle plate 64 shown in FIG. 2A, except that in FIG. 2B, the throttleplate 64 is illustrated as transparent, so as to expose the interior orthe throttle plate 64. Thus, FIGS. 2A and 2B may be described togetherin the description herein.

Throttle plate 64 is shown positioned within boost chamber 46 of anintake as fresh intake air 82 flows through intake conduit 95.Specifically, intake air 82 flows through boost chamber 46 past throttleplate 64. An upstream surface 244 of throttle plate 64, may beperpendicular to the direction of flow of the intake air 82, and mayface the oncoming intake air 82. A downstream surface 246 may be locatedon the opposite side of the throttle plate relative to the upstreamsurface 244, and may therefore not face incoming intake air 82. Thus,intake air 82 may flow through the boost chamber 46, and may contact theupstream surface 244 of the throttle plate 64. Intake air 82, may thenflow around the throttle plate 64, past exterior edges defining acircumference of the throttle plate, past the downstream surface 246,towards the intake valve of cylinder 30.

Throttle plate 64 includes a hollow interior passage 72 which extendsfrom the upstream surface 244 to the downstream surface 246 of thethrottle plate. Said another way, the hollow interior passage 72 extendsthrough the width of the throttle plate 64, such that intake air 82 maypass through the interior passage 72 en route to the intake valve ofcylinder 30. Thus intake air 82 flowing through the boost chamber 46towards the intake valve of the cylinder 30, may flow around thethrottle plate 46, and/or through the interior passage 72. Further, theinterior passage 72 is hollow so that it provides fluidic communicationbetween upstream and downstream of the throttle plate 64, so that intakeair 82 may flow therethrough. The interior passage 72 may be positionedat the center of the throttle plate 64. Thus, hollow interior passage72, may also be referred to in the description herein as hollow centralpassage 72. Specifically, the interior passage 72 may be centered on acentral axis 226 of the throttle plate 64. In the example of FIGS. 2Aand 2B, the central axis of interior passage 72 may coincide with and bethe same as central axis 226 of throttle plate 64. Said another way, thecentral axis 226 may be a central axis that is common with the throttleplate 64, and the interior passage 72. As such, interior passage 72 maybe positioned concentrically within the throttle plate 64. In alternateembodiments, the interior passage 72 may not be positioned at the centerof the throttle plate 64. As such, the central axis of the interiorpassage 72 may not coincide with the central axis 226 of the throttleplate 64 but may be parallel thereto.

The upstream surface 244 and downstream surface 246 of the throttleplate 64 may be flat and/or circular as shown in FIGS. 2A-2B. Since theinterior passage 72 extends from the upstream surface 244 to thedownstream surface 246, the interior passage 72 may form a first opening75 on the upstream surface 244 and second opening 79 on the downstreamsurface 246. The shape of the openings 75 and 79 may be differentdepending on the shape of the interior passage 72. In the example shownin FIGS. 2A and 2B, the interior passage 72 may be shaped as a cylinderwhich narrows towards its middle. Thus, the interior passage 72 may beshaped as an hourglass, where the cross sectional area decreases withincreasing deflection away from each of the openings 75 and 79. However,in other examples, each of the openings 75 and 79 may be rectangular,triangular, oval, or other shape. As such, the interior passage 72, maybe any prismatic shape, which narrows towards the middle.

In this way, the throttle plate 64 may be shaped as a torus, with anouter diameter defining the extent of the throttle plate 64, and aninner diameter defining the interior passage 72. Further, the innerdiameter may not be constant, but may be greatest at the upstream anddownstream surfaces 244 and 246, respectively, and may decrease withincreasing deflection away from the upstream and downstream surface 244and 246. However, the upstream and downstream surfaces 244 and 246,respectively, may be flat as shown in FIGS. 2A-2B.

Vacuum consumption device 140 may be fluidly coupled via conduit 198 toa hollow shaft 74 (shown below in FIGS. 3, 4A, and 6), which in turn isconnected to opening 68 (shown in FIG. 2A) of throttle plate 64. Thehollow shaft may be mounted on bearings coupled to an inner surface ofintake conduit 95. However, in other examples, conduit 198 may bedirectly coupled to the interior passage 72.

When vacuum consumption device 140 demands vacuum, and engine conditionspermit, throttle plate 64 may be adjusted by the controller 12 to a moreclosed position within boost chamber 46. The amount of air flowing pastthe throttle plate 64 may decrease with increasing deflection of thethrottle plate 64 towards a closed position. Said another way, as thethrottle plate 64 is adjusted towards a more closed position, the amountof air permitted to pass around the periphery of the throttle plate 64may decrease. However, as the throttle plate 64 is adjusted towards amore closed position, the amount of air permitted to pass through theinterior passage 72 may increase. As the throttle plate 64 moves towardsa more closed position, a top edge 242, and a bottom edge move moreproximate inside edges of intake conduit 95. As such, the crosssectional flow area of the upstream surface 244 may increase withincreasing deflection towards a more closed position. Said another way,the upstream surface 244 may contact a greater amount of intake air 82with increasing deflection towards a more closed position. With throttleplate 64 situated in a more closed position, a constricted passage maybe created between the inside edge of intake conduit 95 and theperiphery of throttle plate 64. In the example of FIG. 2, constrictedpassages may be created between top edge 242 and the top inside ofintake conduit 95, and bottom edge 232 of throttle plate and the bottominside edge of intake conduit 95. Since the flow past the periphery ofthe throttle plate 64 may decrease with increasing deflection towards amore closed position, the amount of intake air 82 flowing through theinterior passage 72 may increase. Further, since the opening 75 isparallel and flush with the upstream surface 244, as the throttle plate64 is adjusted to a more closed position, the opening 75 may be incontact with a greater amount of intake air 82.

As intake air 82 flows through the interior passage 72, a venturi effectis created, and vacuum may be generated within the interior passage 72.Specifically, as shown in FIG. 2B, the interior passage 72, is widest atthe upstream and downstream surfaces 244 and 246, respectively at eachof the openings 75 and 79. The interior passage 72 narrows towards themiddle. That is, the cross-sectional area of the interior passage 72,decreases between each of the openings 75 and 79 at the upstream anddownstream surfaces 244 and 246, respectively. In examples where theconduit 198 is coupled directly to the interior passage 72, the conduit198 may be coupled to the interior passage 72 at the most narrow pointof the interior passage 72. Intake airflow velocity may reach a highervalue in the constricted portion of the interior passage 72, where theinterior passage 72 narrows, while local static pressure may reach alower value producing a vacuum 84 at or near the location where theconduit 198 is coupled to the interior passage 72. When the vacuum isapplied to the vacuum consumption device, air 86 is drawn from thevacuum consumption device 140 via conduit 198, and in some examplesthrough a hollow shaft in the throttle plate 64 (e.g., hollow shaft 74show in FIGS. 3, 4A, and 6), and then through the interior passage 72and out of the opening 79 formed on the downstream surface 246 of thethrottle plate 64, to join with intake air 82 flowing past throttleplate 64.

The conduit 198 is hollow, so that it may provide fluidic communicationbetween the vacuum consumption device 140 and the interior passage 72.The conduit 198 may be defined by conduit walls 199. Thus, the conduit198 is hollow within the conduit walls 199. A portion of the conduit 198may extend into the interior of the throttle plate 64. Morespecifically, the conduit 198, may extend through an exterior edge ofthe throttle plate 64 to the interior passage 72. However, in otherexamples as shown below with reference to FIGS. 3, 4, and 6, conduit 198may be coupled to a hollow shaft at a location exterior to the throttleplate 64, and the hollow shaft may extend though the throttle plate tothe interior passage 72. In some examples, the conduit 198 or hollowshaft may be physically coupled on a first side of the interior passage72, and may continue to extend into the throttle plate 64 on a secondside of the interior passage 72 directly opposite the first side. Morespecifically, air 86 from conduit 198 may flow into interior passage 72via first aperture 175. However air 86 may also through a secondaperture 176 into a portion of conduit 198 or the hollow shaft thatextends further into the throttle plate 64 on the opposite side of theinterior passage 72 as shown in greater detail below with reference toFIG. 3. As such, in some examples, air 86 may flow through the conduit198, and then in some examples through the hollow shaft, into theinterior passage 72 via first aperture 175, and then across the interiorpassage 72 through second aperture 176, and then back into interiorpassage 72 through second aperture 176, and out the throttle plate 64via the opening 79 positioned on the downstream surface 246. FIG. 3shows a more detailed illustration of the flow of air 86 through theconduit 198 into the interior passage 72.

Thus, the only portion of the throttle plate 64 that may be hollow iswithin the conduit walls 199 of the conduit 198 and/or within the wallsof the hollow shaft, and the interior passage 72. However, in otherexamples, the throttle plate 64 may be entirely hollow, such that theportion of the throttle plate within and outside of the conduit walls199 and the walls of the hollow shaft may be hollow. The conduit walls199 or the walls of the hollow shaft (e.g., hollow shaft 74 shown inFIGS. 3, 4A, and 6) may therefore, be physically coupled to the interiorpassage 72 at the first aperture 175, so that air 86 flowing through theconduit 198 may only flow within the conduit walls 199, and into theinterior passage 72 via aperture 175. As such, interior passage 72 andconduit 198 may be in sealing contact with one another so that air 86flowing through conduit 198 may only flow into interior passage 72, andout of the throttle plate at the downstream surface 246 via the opening79. Thus, no air may flow within throttle plate 64 outside of theinterior passage 72 and conduit 198. Cutting plane M-M′ defines theperspective view of the throttle 64 shown in FIGS. 3-4D below.

Turning now to FIG. 3, it shows an embodiment 300, where throttle plate64 and its arrangement in the intake conduit 95 is shown in more detail.FIG. 3 is a cross sectional view of throttle plate 64 positioned withinintake conduit 95, where the cross sectional plane is taken along lineM-M′ of FIGS. 2A-2B. Note that components previously introduced in FIG.1 and FIGS. 2A-2B are numbered similarly in FIG. 3, and may not bereintroduced.

Throttle plate 64 is positioned in the example of FIG. 3 in a closedfirst position. In the closed first position, the throttle plate 64, isapproximately perpendicular to the walls of the intake conduit 95. Assuch, the flow of intake air 82 around the throttle plate 64 may bereduced. Said another way, the opening that exists between the edges ofthe throttle plate and the walls of the conduit 95 may decrease withincreasing deflection of the throttle plate towards the closed firstposition. In some examples, intake air 82 may not flow around thethrottle plate 64 in-between the top edge 242 and the interior wall ofthe conduit 95, and in-between the bottom edge 232 and the interior wallof the conduit 95. However, in the closed first position, the interiorpassage 72 may be perpendicular to the flow of intake air 82, so thatintake air 82 may flow through the interior passage 72, and thereforethe throttle plate 64, from the upstream surface 244 of the throttleplate 64, to the downstream surface 246.

As described above with reference to FIG. 2, air 86 may be drawn fromthe vacuum consumption device 140 and may travel through conduit 198towards the interior passage 72. However, in the example shown in FIG.3, the conduit 198 may be physically and fluidly coupled to a hollowshaft 74, which may extend radially into the throttle plate 64, and maybe coupled to the interior passage 72. The hollow shaft 74 may bearranged centrally within the throttle plate 64, such that it iscentered on a central vertical axis V-V′ of the throttle plate 64. Insome examples, as shown above with reference to FIG. 2B, a first portion305 of the hollow shaft 74 may be continuous up to the first aperture175 (shown above with reference to FIG. 2B). However, in other examples,as shown in FIG. 3, the first portion 305 of the hollow shaft 74 may becoupled to a first side 309 of the interior passage 72 via the firstaperture 175, and may extend out past the edge of the throttle plate 64,and past the walls of the intake conduit 95, to exterior of the intakeconduit 95. Thus, the first portion 305 of the hollow shaft 74 may bephysically and fluidly coupled on one end to the conduit 198, and on theother end to the interior passage 72, where the conduit 198 and thehollow shaft 74 may be coupled to one another exterior to the intakeconduit 95. As such, the hollow shaft 74 may provide fluidiccommunication between the vacuum consumption device and the interiorpassage 72 of the throttle plate 64. The walls of the hollow shaft 74 donot extend through the interior passage 72. Thus, intake air 82 may flowthrough the interior passage 72 without any obstruction from the hollowshaft 74. However, the hollow shaft 74 may continue on a second side 311of the interior passage 72, where the second side 311 is directlyopposite the first side 309, and may extend further in the throttleplate 64. Thus, an extended second portion 307 of hollow shaft 74 maycontinue on the opposite side of the central axis 226 with respect tothe first portion 305. However, in some examples, the hollow shaft 74may only extend up to the first side 309 of the interior passage 72 atthe first aperture 175, and may not extend further into the throttleplate 64.

In some examples, the only portion of the throttle plate 64 that may behollow is within the walls of the hollow shaft 74, and the interiorpassage 72. However, in other examples, the throttle plate 64 may beentirely hollow, such that the portion of the throttle plate within andoutside of the walls of the hollow shaft 74 may be hollow. The walls ofthe hollow shaft 74 may therefore, be physically coupled to the interiorpassage 72 at the first aperture 175 shown in FIG. 2A, so that air 86flowing through the conduit 198 may only flow within the hollow shaft74, and into the interior passage 72. As such, interior passage 72 andhollow shaft 74 may be in sealing contact with one another so that air86 flowing through hollow shaft 74 may only flow into interior passage72, and out of the throttle plate at the downstream surface 246 via theopening 79. Therefore, air 86 may flow from the vacuum consumptiondevice 140 through the hollow shaft 74, and into the interior passage 74via the first aperture 175 formed where the hollow shaft 74, andinterior passage are coupled to one another. Thus, no air may flowwithin throttle plate 64 outside of the interior passage 72 and hollowshaft 74.

The interior passage 72 may comprise first inner walls 373, and secondinner walls 375, positioned on opposite sides of the hollow shaft 74.The first inner walls 373 may be angled outwardly in an upstreamdirection away from the hollow shaft 74, while the second inner walls375 may be angled outwardly in a downstream direction away from thehollow shaft 74. Specifically, one of the first inner walls 373 moreproximate the top edge 242 may be coupled on one end to the upstreamsurface 244 of the throttle plate 64, and on the other end, to a portionof the hollow shaft 74 more proximate the upstream surface 244, and maybe angled outwardly from the hollow shaft 74 to the upstream surface244. The other one of the first inner walls 373 more proximate thebottom edge 232, may be coupled on one end to the upstream surface 244of the throttle plate 64, and on the other end, to a portion of theextended portion 305 of the of the hollow shaft 74 more proximate theupstream surface 244, and may be angled outwardly from the hollow shaft74 to the upstream surface 244. Similarly, one of the second inner walls375 more proximate the top edge 242, may be coupled on one end to thedownstream surface 246 of the throttle plate 64, and on the other end,to a portion of the hollow shaft 74 more proximate the downstreamsurface 246, and may be angled outwardly from the conduit wall to thedownstream surface 246. Additionally, the other one of the second innerwalls 375 more proximate the bottom edge 232, may be coupled on one endto the downstream surface 246 of the throttle plate 64, and on the otherend, to a portion of the extended portion 305 of the hollow shaft 74more proximate the downstream surface 246, and may be angled outwardlyfrom the conduit wall to the downstream surface 246.

As such, the interior passage 72 may be narrower where it intersectswith the hollow shaft 74, than at the upstream and downstream surfaces244 and 246, respectively. More specifically, a constricted portion 323of interior passage 72 may be a portion of the interior passage 72 wherethe interior passage 72 is most narrow. The constricted portion 323, maytherefore be the portion of the interior passage 72, between each of thefirst inner walls 373, and each of the second inner walls 375. In theexample shown in FIG. 3, the constricted portion 323 of the interiorpassage 72, may span the diameter of the hollow shaft 74. However, inother examples, the constricted portion 323 may wider than the diameterof the hollow shaft 74. In some examples, the cross sectional area ofthe interior passage 72, may be uniform in the constricted portion 323of the interior passage. The interior passage 72 may therefore becomeincreasingly narrow with increasing deflection towards the hollow shaft74 and away from the upstream and downstream surfaces 244 and 246,respectively. Then, at the constricted portion 323, the interior passage72 may be uniform in cross sectional area. Airflow through the interiorpassage 72 may therefore be constricted as it nears the constrictedportion 323 near the center of the throttle plate 64 where the hollowshaft 74 is coupled to the interior passage 72. Thus, as air 82 flowsthrough the interior passage 72, vacuum is generated at the constrictedportion 323 via a venture effect at the constricted portion 323, whichin the example shown in FIG. 3 coincides with where the hollow shaft 74is fluidically coupled to the interior passage 72. Thus, the hollowshaft 74, may be physically and fluidically coupled to the interiorpassage 72 at the constricted portion 323 of the interior passage 72.Thus, the aperture 175 shown in FIG. 2B may be positioned at theconstricted portion 323 of the interior passage 72. Air 86 from thevacuum consumption device 140 may be drawn through passage 198 andhollow shaft 74 into the interior passage 72 at the constricted portion323 of the interior passage 72.

Thus, the first portion 305 of the hollow shaft 74, may be fluidlycoupled on one end to the constricted portion 323 of the interiorpassage 72, and on the other end to the conduit 198. Specifically, thehollow shaft 74, may be coupled to a first side 309 of the constrictedportion 323 of the interior passage 72, via a first aperture 175. Assuch, air 86 may flow from the vacuum consumption device 140 through thehollow shaft 74, and into the constricted portion 323 of the interiorpassage 72 via the first aperture 175 formed where the hollow shaft 74is coupled to the constricted portion 323 of the interior passage 72.

All or a portion of the air 86 entering the interior passage 72 fromconduit 198 and hollow shaft 74, may flow across the interior passage72, into extended portion 305 of the hollow shaft 74 before exiting thethrottle plate 64 through the interior passage 72. Thus, a portion ofall of the air 86 may pass through the interior passage 72, into theextended portion 305, back into the interior passage 72, and then outthe throttle plate 64 through the interior passage 72, downstream of thehollow shaft 74. However, in other examples, air 86 may pass directlyinto the interior passage 72 from hollow shaft 74 and out of thethrottle 64. After exiting hollow shaft 74, and entering interiorpassage 72, the air 86 from the vacuum consumption device 140 may joinwith intake air 82 flowing through the interior passage 72 from theupstream surface 244 to the downstream surface 246. As such, a mixtureof intake air 82 and air 86 from the vacuum consumption device may exitthe throttle 64 at the downstream surface 246, and may continue in theconduit 95 towards the intake valve of cylinder 30 shown in FIG. 1.

In the example of FIG. 3, hollow shaft 74, is shown penetrating into thethrottle plate 64 from the top edge 242, towards the center of thethrottle plate 64, and connecting with the constricted portion 323 ofthe interior passage 72. Said another way, the hollow shaft 74, mayextend radially inward from the top edge 242 of the throttle plate 64,and may be coupled to the interior passage 72, to provide fluidiccommunication between conduit 198 and the interior passage 72. However,in other examples, as shown below with reference to FIGS. 4A-4D, thehollow shaft 74 may extend radially inward towards the interior passage72, from locations other than the top edge 242 around the circumferenceof the throttle plate 64.

Turning now to FIGS. 4A-4D they show embodiments where the hollow shaft74 may be coupled to the throttle plate 64 along the axis of rotation ofthe throttle plate 64. Thus, FIGS. 4A-4D, show the relative positioningof the hollow shaft 74 and the throttle plate 64, as the throttle plate64 is adjusted to different example positions that may occur duringengine operation. Similar to FIG. 3, FIGS. 4A-4D show cross sectionalviews of throttle plate 64 positioned within intake conduit 95, wherethe cross sectional plane is taken along line M-M′ of FIGS. 2A-2B. FIG.4A, shows the throttle plate 64 in the closed first position shown abovewith reference to FIG. 3. FIGS. 4B and 4C, show the throttle plate 64 inintermediate second positions, where more air may flow past throttleplate 64 in the intermediate second positions than in the closed firstposition. FIG. 4D, shows the throttle plate 64 in an open thirdposition, where more air may flow past the throttle plate 64 in the openthird position than in the intermediate second positions. Note thatcomponents previously introduced in FIG. 1 and FIGS. 2A-2B are numberedsimilarly in FIG. 3, and may not be reintroduced.

FIG. 4A shows an embodiment 400, where throttle plate 64 is in theclosed first position. Thus, throttle plate 64 may be approximatelyperpendicular to the walls of conduit 95. Throttle plate 64 may rotateabout an axis of rotation R-R′ shown in FIG. 4A. Thus, in FIGS. 4B-4D,throttle plate 64 may be shown rotated about the axis of rotation R-R′in different positions. A portion of conduit 198 exterior to conduit 95is shown in dotted lines. However, as explained above with reference toFIG. 3, hollow shaft 74 may extend radially inward from a location onthe circumference of throttle plate 64, to the interior passage 72. Asshown in the examples of FIGS. 4A-4D, the hollow shaft 74 may extendradially between the interior passage 72, and an edge of the throttleplate 64, along the axis of rotation R-R.′ Thus, the walls of the hollowshaft 74 may be parallel to the axis of rotation R-R.′ As such, thehollow shaft 74 may not move, but may rotate as the throttle plate 64rotates about the axis of rotation R-R.′ However, in other examples, thehollow shaft 74 may be free to rotate relative to the throttle plate 64,and as such may remain in approximately the same position duringrotation of the throttle plate 64. In such examples, the conduit 198 maybe free to rotate relative to the hollow shaft 74, and as such mayremain in approximately the same position during rotation of thethrottle plate 64.

FIG. 4B shows an embodiment 425, where the throttle plate 64 is rotatedalong the axis of rotation R-R,′ relative to the closed first positionshown in FIG. 4A to an intermediate second position. Specifically,throttle plate 64 is rotated in FIG. 4B so that the top edge 242, movesupstream in the conduit 95, and the bottom edge 232 moves downstream inconduit 95 relative to their positioning shown in the closed firstposition of FIG. 4A. Put more simply, in FIG. 4B, the throttle plate 64is shown rotated clockwise from the closed first position. However, theconduit 198 and/or hollow shaft 74 may remain in the same position inFIG. 4B, as in FIG. 4A, since they may be centered on the axis ofrotation R-R′ of the throttle plate 64.

FIG. 4C shows an embodiment 450, where the throttle plate 64 is rotatedalong the axis of rotation R-R,′ relative to the closed first positionshown in FIG. 4A to an intermediate third position. Specifically,throttle plate 64 is rotated in FIG. 4C so that the top edge 242, movesdownstream in the conduit 95, and the bottom edge 232 moves upstream inconduit 95 relative to their positioning shown in the closed firstposition of FIG. 4A. Put more simply, in FIG. 4C, the throttle plate 64is shown rotated counterclockwise from the closed first position shownin FIG. 4A. However, the conduit 198 and/or hollow shaft 74 may remainin the same position in FIG. 4C, as in FIG. 4A, since they may becentered on the axis of rotation R-R′ of the throttle plate 64.

In both the intermediate second position and intermediate third positionshown in FIGS. 4B and 4C respectively, the amount of intake air 82flowing through the interior passage 72, may be approximately the same,and may be less than that in the closed first position of the throttleplate 64 shown in FIG. 4A. Said another way, more intake air 82, mayflow through the interior passage 72, in the closed first position ofthe throttle plate 64 shown in FIG. 4A, than when the throttle plate 64is rotated away from the closed first position as shown in FIGS. 4B and4C. Since the amount of intake air 82 flowing through the interiorpassage 72 may be less when the throttle plate 64 is rotated away fromthe closed first position, the amount of vacuum generated at theconstricted portion 323 of the interior passage 72, may be less thanwhen the throttle plate 64 is adjusted to the closed first position.Thus, as the throttle plate 64 is adjusted towards the closed firstposition where the throttle plate 64 is approximately perpendicular tothe walls of the conduit 95, the amount of air flowing through theinterior passage 72 may increase, and in turn the amount of vacuumgenerated due to the venturi effect at the constricted portion 323 ofthe interior passage 72 may increase. In this way, the amount of air 86flowing from the vacuum consumption device 140, to the interior passage72 may increase with increasing deflection of the throttle plate 64towards the closed first position, where the throttle plate 64 isapproximately perpendicular to the walls of the conduit 95.

FIG. 4D shows an embodiment 475, where the throttle plate 64 is rotatedalong the axis of rotation R-R,′ relative to the closed first positionshown in FIG. 4A to an open fourth position. Specifically, in the openfourth position, the throttle plate 64 is rotated in FIG. 4C so that thethrottle plate 64 is parallel to the walls of the conduit 95. However,the hollow shaft 74 and/or conduit 198 may remain in the same positionin FIG. 4D, as in FIG. 4A, since they may be centered on the axis ofrotation R-R′ of the throttle plate 64. Intake air 82 may flowcompletely around the throttle plate 64, since the throttle plate 64 isparallel to the conduit 95. As such, less air may flow through theinterior passage 72 when the throttle plate is in the open fourthposition, than in the intermediate second and third positions shown inFIGS. 4B and 4C, respectively.

Turning now to FIGS. 5 and 6, they show throttle plate 64 and itsarrangement in the intake conduit 95 in more detail. FIG. 5 is aschematic diagram of boost chamber 46 with throttle plate 64 positionedwithin and viewed from the side of intake conduit 95. FIG. 6 is a crosssectional view of boost chamber 46 within intake conduit 95, in a crosssectional plane along line B-B′ of FIG. 3. In the depicted example,throttle plate 64 is situated within intake conduit 95 and leaning awayfrom the viewer such that bottom edge 232 is lifted towards the viewer.Note that components previously introduced in FIG. 1 and FIG. 2 arenumbered similarly in FIGS. 3 and 4, and not reintroduced.

Throttle plate 64 is positioned in the examples of FIG. 5 and FIG. 6 ina more closed position within intake conduit 95 and boost chamber 46than the open third position shown above with reference to FIG. 4D. Thedepicted more closed position enables more vacuum generation than wouldbe obtained in the open third position. A region 65 is enclosed withinwalls 67 of throttle plate 64. In some examples, region 65 may behollow. However, in other examples region 65 may not be hollow. FIG. 6depicts the placement of interior passage 72 within throttle plate 64.Specifically, the interior passage 72 may be centered on the center ofthe throttle plate 64. As shown in FIG. 6, the interior passage 72 maybe cylindrical, and as such the first opening 75 may be circular.However, the size, and location of the interior passage 72 may bedifferent from the example shown herein. Vacuum consumption device 140is connected via conduit 198, and hollow shaft 74 to opening 68 ofthrottle plate 64. Hollow shaft 74 may be fluidly coupled to conduit 198in a longitudinal manner. Hollow shaft 74 may extend radially inwardfrom the opening 68 towards the interior passage 72, as shown by thedotted lines in FIG. 6, and may be fluidly coupled to the interiorpassage 72. As such, vacuum consumption device 140 may be in fluidiccommunication with interior passage 72 via conduit 198 and hollow shaft74.

A position of throttle plate 64 may be adjusted by motor 81 that isconnected to throttle plate 64 via shaft 76. Shaft 76 may not be hollow.Throttle plate 64 may be mounted on hollow shaft 74 and shaft 76 suchthat shafts 74 and 76 are perpendicular to the edge of the throttleplate. Further, throttle plate 64 may be joined to shaft 76 and hollowshaft 74 at its edge via one or more of various joining methodsincluding welding, adhesion and fastening. Other joining methods notlisted herein may also be used. Throttle plate 64 may in turn be fittedwithin a throttle body (not shown). Each of the shafts 74 and 76, may bemounted on respective bearings 654 and 658 which may be bolted to theirrespective housings 655 and 657. Thus, as throttle plate 64 is rotatedto different throttle angles within intake conduit 95, shaft 74 and 76may spin, supported by respective bearings 254 and 258. Motor 81 may bepowered by a system battery and may receive operating commands fromcontroller 12 to adjust the position of throttle plate 64 via shaft 76based on engine conditions. By varying a position of shaft 76, motor 81may adjust an opening and closing of throttle plate 64.

Thus, in one example, throttle plate 64 may be adjusted by motor 81 to amore closed position in response to an increase in vacuum demand at thevacuum consumption device 140. As intake air 82 flows through interiorpassage 72 of throttle plate 64, vacuum may be generated herein. Thisvacuum may be applied to vacuum consumption device 140 by flowing airfrom vacuum consumption device 140 through conduit 198 and hollow shaft74, into interior passage 72. Air drawn from vacuum consumption device140 may then be streamed through interior passage 72 along with intakeairflow, e.g. intake air 82, towards the intake valve of cylinder 30.

In this way, a system may comprise an engine including an intakeconduit, a throttle plate mounted on a hollow shaft positioned in theintake conduit, the throttle plate having a hollow interior passageextending from an upstream surface to a downstream surface of thethrottle plate, for flowing intake air through the throttle plate, and acontroller with computer-readable instructions stored in non-transitorymemory. The computer-readable instructions may include instructions forin response to vacuum demand, adjusting a position of the throttle plateto generate vacuum at a constricted portion of the interior passage asintake air flows through the interior passage. In some examples, thesystem may further comprise a vacuum consumption device, wherein thehollow shaft of the throttle plate is fluidly coupled to the vacuumconsumption device and the constricted portion of the interior passage,where the hollow shaft extends radially outward from the constrictedportion of the interior passage through the throttle plate, and throughthe intake conduit along an axis of rotation of the throttle plate, andwherein the controller includes further instructions for applying thegenerated vacuum to the vacuum consumption device. The adjusting of thethrottle plate may be in response to the vacuum demand of the vacuumconsumption device, where the controller may be configured to move thethrottle plate towards a more closed position where the intake airflowthrough the interior passage may increase to increase vacuum generationat the throttle plate as the vacuum demand of the vacuum consumptiondevice increases. In some examples, the interior passage is narrowest atthe constricted portion, whereby a venturi effect may be created at theconstricted portion of the interior passage. Further, the hollow shaftmay in some examples comprise a first portion that extends radiallyinward from exterior the throttle plate and may fluidly coupled to afirst side of the constricted portion of the interior passage via afirst opening, and a second portion that may be fluidly coupled to asecond side of the constricted portion of the interior passage via asecond opening, the second side directly opposite the first side, andwhere the second portion may extend from the second side radiallyoutward into the throttle plate so that a portion of gasses in theinterior passage may flow into the second portion and back into theinterior passage.

Turning now to FIG. 7, it shows an example routine 700 that a controller(e.g., controller 12 shown in FIG. 1) may perform to adjust a throttleplate (e.g., throttle plate 64 shown in FIGS. 1-6) position in responseto vacuum demand from a vacuum consumption device coupled to thethrottle plate. In the description herein, the term “throttle” may alsobe used to refer to “throttle plate.” Additionally, the controller maymodify one or more engine operating parameters responsive to theadjusting of the throttle plate in order to maintain engine torque.

At 702, engine operating conditions may be determined. Engine operatingconditions may include engine speed, torque demand, combustion air-fuelratio, boost pressure, manifold absolute pressure, mass airflow, enginetemperature, etc. Once engine operating conditions are estimated, at704, an initial throttle position may be determined and set based onthese engine operating conditions. For example, as the operator torquedemand increases, the throttle may be moved to a more open position toincrease intake airflow. As another example, if combustion air-fuelratio is determined to be leaner than a desired stoichiometric value,the throttle may be set to a more closed position to reduce intakeairflow. In yet another example, if engine idling conditions are met,the throttle may be moved to a fully closed position.

At 706, routine 700 may determine if vacuum is desired by a vacuumconsumption device (e.g., vacuum consumption device 140 shown in FIG. 1)coupled to the throttle. In one example, vacuum may be demanded when thevacuum consumption device is actuated. In another example, if the vacuumconsumption device includes a vacuum reservoir, it may be determined ifthe vacuum requirement of the device exceeds the vacuum available in thereservoir. If it is determined that vacuum is not desired, at 712, theinitial throttle position may be maintained and the routine ends. Thethrottle position may then continue to be adjusted based on engineoperating conditions only, and not based on vacuum requirement of thevacuum consumption device.

On the other hand, if it is determined that the vacuum consumptiondevice requires vacuum assistance, at 708, routine 700 may assesswhether engine conditions allow a change in throttle position. Inparticular, it may be determined if the engine conditions permit achange in the throttle position towards a more closed position whereintake airflow to the engine is reduced. As such, there may be engineconditions where changes in throttle position may be tolerated withoutaffecting engine performance. In addition, there may be conditions wherethe throttle position is limited or constrained. For example, if thevehicle is accelerating on a highway and engine speed is higher than athreshold, the throttle may be positioned in a mostly open or fully openposition to allow higher airflow than when the throttle is in a moreclosed position. In this situation, the throttle position may not bemoved to a more closed position for generating vacuum as it wouldadversely affect engine torque output and performance. Thus, if itdetermined that the position of the throttle cannot be adjusted, at 710,the controller maintains the throttle at its initial position and theroutine ends. The throttle position may then continue to be adjustedbased on engine operating conditions only, and not based on the vacuumrequirement of the vacuum consumption device.

However, if it is assessed that engine conditions permit a change inthrottle position, and more specifically the conditions permit adecrease in throttle position, at 714, the throttle may be moved towardsa more closed position than the initial position. The adjustment to theposition of the throttle may depend on the level of vacuum desired bythe vacuum consumption device. For example, if a higher level of vacuumis desired, the throttle may be moved further towards a fully closedposition (e.g., the throttle may be fully closed). On the other hand, ifa lower level of vacuum is desired, the controller may adjust thethrottle to a slightly closed or partially closed position. Thus, as thelevel of desired vacuum from the vacuum consumption device increases,the throttle may be moved towards a more closed position. In oneexample, if it is determined at 708 that the throttle is already in aclosed position during engine idling, the throttle position may beretained, at 714, without further adjustments.

Next, at 716, vacuum may be generated at the throttle plate as intakeair flows through a interior passage (e.g., interior passage 72 shown inFIGS. 1-6) of the throttle. Thus, the method 700 at 716 may includeflowing intake air through the interior passage. As elaboratedpreviously, a venturi effect may be created by the flow of intake airthrough a constricted passage (e.g., constricted portion 323 shown inFIGS. 3-4D) of the interior passage. Specifically, the interior passagemay be shaped such that it is narrower towards the middle than at eitherend. In this way, a venture effect may be created at the constrictedportion of the interior passage, and vacuum may be generated within theconstricted portion of the interior passage. At 718, the generatedvacuum may be applied to the vacuum consumption device to enable thedevice to be actuated or operated. For example, where the vacuumconsumption device is a brake booster, the generated vacuum may beapplied to enable wheel braking. As another example, where the vacuumconsumption device is a fuel vapor canister, the generated vacuum may beapplied to enable canister purging to the engine intake. As yet anotherexample, where the vacuum consumption device is a vacuum actuated valve,the generated vacuum may be applied to enable valve actuation. As vacuumis applied to the vacuum consumption device, air is received from thevacuum consumption device at the throttle plate. As described earlier,air may flow from the vacuum consumption device, through a conduit(e.g., conduit 198 shown in FIGS. 1-6) coupled to a hollow shaft (e.g.,hollow shaft 74 shown in FIGS. 3-6) of the throttle plate and outthrough the interior passage into the intake. Thus, the air from thevacuum consumption device is received at the throttle, facilitating airflow control.

At 720, one or both of fuel injection amount and injection timing may beadjusted based on the throttle position, and existing airflow, tomaintain engine torque. Existing airflow may be a combination of freshintake air that flows past the perforated edge of the throttle and airflowing from the vacuum consumption device through the throttle plateinto the intake. In one example, the fuel injection amount and/or timingmay be adjusted to maintain a cylinder air-fuel ratio at or close to adesired ratio, such as stoichiometry. In another example, fuel injectionamount and/or timing may be modified to maintain engine combustion fortorque. In yet another example, one or both of fuel injection timing andfuel injection amount may be varied to maintain each of engine torqueand a stoichiometric air fuel ratio.

In one example, during engine idling conditions, as the throttle isadjusted to a fully closed position, airflow via the throttle is reducedwhile airflow from the vacuum consumption device into the intakemanifold is increased. Based on the total airflow being smaller, a fuelinjection amount may be decreased to maintain air-fuel ratio. The fuelinjection amount may be reduced by decreasing a pulse width of the fuelinjection. Further, fuel injection timing may be advanced or retardedbased on engine torque requirement.

At 722, one or more engine operating parameters may be varied inresponse to the adjustment of throttle position and the flowing of airfrom the vacuum consumption device. Engine operating parameters may bemodified to maintain engine torque output. For example, boost pressuremay be increased at 724 as the throttle plate is moved to a more closedposition at 714. To increase boost pressure, a wastegate coupled acrossan exhaust turbine may be adjusted to a less open position to allow alarger quantity of exhaust gases to flow past the exhaust turbine. Byincreasing boost pressure in the boost chamber within the intake, a dropin engine torque resulting from the throttle closing can be compensatedfor.

Engine torque output may also be maintained by decreasing a rate ofexhaust gas recirculation (EGR) at 726. As the throttle is moved to amore closed position, an EGR valve in an EGR passage coupling the engineexhaust to the engine intake may be adjusted to a more closed positionto allow a smaller proportion of exhaust gases to be recirculated intothe intake. Thus, by reducing the flow of exhaust residuals into theintake, engine dilution is reduced, and the aircharge within enginecylinders may comprise a larger proportion of fresh intake air allowingthe engine to maintain its torque output.

At 728, valve timing may be adjusted to retain engine torque levels. Inone example, the intake valve may be held open for a longer duration toallow more fresh air into the cylinder. In another example, exhaustvalve timing may be modified to reduce the proportion of internal EGRwithin the cylinder. Further still, each of intake an exhaust valvetiming may be adjusted to vary an amount of valve overlap. For example,valve overlap may be reduced to improve engine torque output.

It will be appreciated that the controller may select one or more of thevarious engine operating parameters described above to maintain torquebased on existing operating conditions. For example, during a firstcondition, where the vehicle is operating under steady state drivingconditions when the throttle position is modified to generate vacuum,the controller may only increase boost pressure but not reduce EGR tomaintain engine torque output. During a second condition, as thethrottle is closed, boost pressure may be maintained while EGR dilutionis reduced. In another example, during a third condition, each ofinternal and external EGR reduction may be used. For example, an exhaustvalve may be closed relatively early to reduce internal EGR within thecylinder and an opening of the EGR valve for external EGR may bedecreased simultaneously to reduce external EGR into the intake. Duringa fourth condition, as the throttle position is closed, the controllermay reduce EGR while also increasing boost pressure. Still othercombinations may be possible.

Next at 730, routine 700 may confirm that sufficient vacuum has beengenerated to meet the demand of the vacuum consumption device. If it isdetermined that the demand has not been met, at 734, the throttleposition set at 714 may be maintained and vacuum may continue to begenerated for a longer duration. In another example, if the throttle isnot fully closed at 714, the throttle may be moved to a fully closedposition to generate more vacuum, if engine operating conditions allowthis adjustment. Routine 700 may then return to 730 to determine ifvacuum demand has been met.

If it is determined that sufficient vacuum has been generated for thevacuum consumption device, at 732, the throttle may be adjusted back toits initial position. Alternatively, the throttle may be moved to aposition based only on the existing engine operating conditions.

In this way, a position of the throttle may be adjusted by thecontroller in response to a vacuum demand from the vacuum consumptiondevice. As the demand for vacuum from the vacuum consumption deviceincreases, the throttle may be moved to a more closed position. Further,changes in engine torque that occur from the decrease in throttleopening and the flowing of air from the vacuum consumption device may becounteracted by varying one or more of engine operating parameters suchas boost pressure, valve timing and EGR. Thus, boost pressure may beincreased, EGR flow may be reduced and valve timings may be altered tomaintain engine torque output. Further, one or both of fuel injectionamount and injection timing may be modified to maintain enginecombustion at or around stoichiometry.

In this way, a method for an engine may comprise adjusting a position ofa throttle plate with a hollow central passage, and generating vacuum ata constricted portion of the central passage, via intake airflow throughthe central passage of the throttle plate. The method may furthercomprise applying the generated vacuum to a vacuum consumption devicefluidly coupled to the constricted portion of the central passage via ahollow shaft, the vacuum consumption device including a brake booster.Additionally or alternatively, the method may comprise, during theapplying of generated vacuum, flowing air from the vacuum consumptiondevice through the hollow central passage of the throttle plate into theintake airflow through the central passage. In some examples, theadjusting of the throttle plate may be based on a vacuum demand of thevacuum consumption device, the adjusting including moving the throttleplate towards a more closed position as the vacuum demand of the vacuumconsumption device increases. Additionally, the method may compriseadjusting an engine operating parameter responsive to one or more of theadjusting the position of the throttle plate and the flowing air fromthe vacuum consumption device to maintain engine torque output. Theoperating parameter may include boost pressure, and thus the method mayinclude increasing boost pressure as the throttle plate is moved towardsthe more closed position. Increasing boost pressure may comprisereducing an opening of a wastegate coupled across an exhaust turbine. Inother examples, the operating parameter may include exhaust gasrecirculation (EGR), and as such the method may include decreasing arate of EGR as the throttle plate is moved towards the more closedposition. In still further examples, the operating parameter maycomprise intake valve timing. As such, the method may include increasinga duration of intake valve opening as the throttle plate is movedtowards a more closed position. Additionally or alternatively, themethod may further comprise, adjusting one or more of a fuel injectionamount and fuel injection timing based on each of the intake airflowthrough the central passage and the air flowing from the vacuumconsumption device through the constricted portion of the centralpassage into the intake airflow through the central passage to maintainengine combustion at or around stoichiometry.

Turning now to FIG. 8, it illustrates map 800 depicting an exampleintake throttle position adjustment based on a demand for vacuum from abrake booster and modifications in engine operating parameters inresponse to the throttle position adjustment. Map 800 shows brake pedalposition at plot 802, brake booster vacuum level at plot 804, boostpressure at plot 806, a wastegate position at 808, EGR valve position atplot 810, throttle position at plot 812, engine torque output at plot814, and vehicle speed, Vs, at plot 814. All the above are plottedagainst time on the X-axis. Line 807 represents a minimum thresholdvacuum in the brake booster reservoir.

Prior to time t1, a vehicle may be moving in a steady state conditionwith moderate speed. The throttle may be at a partly open position toallow adequate airflow into the intake, the throttle opening based onthe operating conditions such as the vehicle speed and the operatordemanded torque. Further, engine torque output and boost pressure may beadjusted to moderate levels based on the operating conditions. In thedepicted example, the engine is operating with the wastegate at a mostlyclosed position to provide the demanded boost pressure. Brake pedal isin a released (or “off”) position and vacuum in the brake boosterreservoir is sufficient, as indicated by the brake booster vacuum beinghigher than vacuum threshold 807. In addition, prior to t1, based onengine operating conditions such as engine speed and load conditions,the EGR valve may be held in a more open position to permit a higherflow of exhaust residuals into the intake, to improve engine fueleconomy and reduce NOx emissions.

At t1, the brake pedal may be applied by the operator upon which vacuumin the brake booster reservoir is consumed to enable wheel braking. Asbrake application continues, the quantity of vacuum in the reservoirreduces. However, the level of vacuum within the reservoir remains abovethreshold 807. Due to brake application, engine torque output andvehicle speed decrease. In addition, to reduce the engine torque outputand vehicle speed, the throttle may be adjusted to a more closedposition. The wastegate may also be moved to a more open position toenable boost pressure to be reduced.

At t2, the brake pedal is released and the vehicle resumes steady statetravel conditions similar to those prior to t1. Based on the prevalentoperating conditions, the throttle is moved towards a more open positionto increase engine torque output. In addition, boost pressure isincreased by moving the wastegate to a more closed position. As aresult, vehicle speed may increase.

At t3, the brake pedal may be applied again. Brake pedal application att3 may be more forceful (e.g., depressed further and faster) as comparedto the brake pedal application at t1. As a result, a steeper drop invacuum levels within the brake booster reservoir is observed. Inparticular, the harder brake pedal application at t3 may result invacuum depletion to below threshold level 607 at the reservoir. As thebrakes are applied, between t3 and t4, vehicle speed and engine torqueoutput fall sharply. The throttle may be moved to a more closed positionand the wastegate may be moved to a more open position, to reduce boostpressure and engine output. Serendipitously, the throttle closing alsoenables vacuum to be produced at the throttle, which may be applied tothe brake booster during the brake application. In particular, as thethrottle is moved to the more closed (e.g., fully closed) position, airflowing past the constriction between the throttle and the intakepassage results in a venturi effect and vacuum is generated at theperforated edge of the throttle plate.

At t4, the brake booster vacuum level falls below threshold 807. Inresponse to drop, a demand for additional vacuum may be received by thecontroller. The brakes may be released at t4 and the vehicle may travelat a slower speed between t4 and t5. However, due to the vacuum demand,the throttle may be adjusted to a fully closed position and may bemaintained at the closed position to generate vacuum via intake airflowpast the perforated edge of the throttle plate. The generated vacuum isapplied to the brake booster until vacuum in the brake booster reservoiris above threshold 807. In an alternate example, the controller maymaintain the throttle at the more closed position existing before t4until the vacuum level in the reservoir is above the threshold. Betweent4 and t5, the vacuum level in the reservoir may rise towards threshold807, and the throttle may be moved to a nominal open position based onexisting engine operating conditions. While the throttle is held closedfor vacuum generation, the wastegate may be moved to a more closedposition to increase boost pressure and prevent a decrease in enginetorque output. Additionally, the EGR valve may be adjusted to a moreclosed position to reduce the flow of exhaust gas residuals into theintake and assist in maintaining engine torque.

At t5, while vacuum is being generated at the throttle, the operator mayapply an accelerator pedal to sharply increase vehicle speed. Forexample, the operator may be accelerating on a highway to pass othervehicles and may fully depress the accelerator pedal. In response toaccelerator pedal application (not shown), the throttle may be moved toa fully open position, also termed a wide open throttle position, toallow maximum airflow into the intake and into the cylinders. Thus, inresponse to an elevated torque request being received while the throttlewas held at the more closed position for vacuum generation, the throttlemay be opened and further vacuum generation may be aborted until engineconditions permit reclosing of the throttle. Due to throttle opening,vacuum levels within the brake booster reservoir remain at or aroundthreshold 807 beyond t5. The EGR valve may be fully closed during wideopen throttle conditions to reduce engine dilution and improve enginetorque output. Simultaneously, the wastegate may also be moved to afully closed position so that boost pressure can be increased rapidly,enabling a significant increase in engine torque. Between t5 and t6, thevehicle speed may rise sharply in response to the accelerator pedalapplication, and then as the accelerator pedal is gradually released,the vehicle speed may fall at or around t6. Engine torque and boostpressure may follow a similar path and the throttle may be moved from afully open position to a partly open position at t6 based on existingoperating conditions. Between t6 and t7, the vehicle may travel atsteady state conditions wherein the vehicle speed, torque, and boostpressure return to levels prior to t1. Further, the EGR valve and thewastegate are returned to nominal positions where EGR valve is more openand the wastegate is more closed.

At t7, the brake pedal may be applied with less force than brake pedalapplication at t1 or t3. Thus, vacuum in the brake booster reservoir maybe consumed to a lesser extent. However, since the vacuum levels withinthe reservoir are just at or around threshold 807, the application ofbrakes at t7 results in vacuum levels decreasing below threshold 807between t7 and t8. As the brakes are applied, vehicle speed and enginetorque reduce and the throttle may be moved to a more closed position.In addition, the throttle may be held at the more closed position sothat vacuum can be generated for brake application. The EGR valve staysin its mostly open position while boost pressure may decrease slightlyas the wastegate is opened slightly.

At t8, the brake pedal may be released and the throttle may be moved toa partly open position. Thus between t8 and t9, engine torque may riseand vehicle speed may increase. At t9, since steady state drivingconditions may exist, and the vacuum levels are below threshold 807, thecontroller may move the throttle to a mostly closed position to generatevacuum. Between t9 and t10, therefore, vacuum levels within the brakebooster reservoir increase steadily until adequate vacuum levels areachieved at t10. To prevent a reduction in engine torque between t9 andt10 as the throttle is moved to a more closed position, boost pressuremay be increased by moving the wastegate to a more closed position att9. The controller may decide to use boost pressure alone and not reduceEGR levels for maintaining engine torque output. Therefore, the EGRvalve is retained at a mostly open position.

At t10, vacuum demand is met and the throttle may be returned to apartly open position. Simultaneously, the wastegate may be moved to amore open position and boost pressure may reduce to a level similar tothat prior to t1.

In this way, a throttle plate configured with an interior passage whichextends through the plate may be positioned in an engine intake passageto generate vacuum from intake airflow when adjusted to a more closedposition. The throttle plate may be mounted on a hollow shaft thatconnects the throttle plate to a vacuum consumption device. In responseto vacuum demand from the vacuum consumption device, the position of thethrottle plate may be adjusted to a more closed position to increasevacuum generation as the demand for vacuum increases. As the opening ofthe throttle plate within the engine intake is decreased, engine torqueoutput may be sustained by modifying one or more of boost pressure, EGRflow and valve timing.

In another representation, a method for an engine may compriseconnecting a vacuum consumption device via a hollow shaft to a throttleplate positioned in an engine intake passage, the throttle plate havinga hollow interior passage; and decreasing an opening of the throttleplate when the vacuum consumption device demands vacuum to increasevacuum production at a constricted portion of the hollow interiorpassage. The vacuum consumption device may be one of a brake booster, afuel vapor canister, and a vacuum actuated valve. In some examples, themethod may further comprise increasing boost pressure responsive to thedecreasing to maintain an engine torque output, where the boost pressuremay be increased by increasing a closing of a wastegate coupled acrossan exhaust turbine via an electronic controller. In further examples,the method may comprise reducing a flow of exhaust residuals from anengine exhaust to the intake passage in response to decreasing theopening of the throttle plate to maintain an engine torque output.Additionally or alternatively, the method may comprise adjusting one ormore of a fuel injection amount and a fuel injection timing responsiveto the decreasing to maintain engine combustion at stoichiometry.

In another representation, a method for an engine may comprise adjustinga position of a throttle plate with a interior passage to generate avacuum within the throttle plate positioned inside an intake of theengine and a gas from outside the engine may be drawn through theinterior passage via the vacuum and into intake airflow flowing throughthe interior passage.

In this way, the functions of an aspirator may be combined with those ofa throttle, enabling a reduction in packaging space. Additionally, byremoving the need for a separate aspirator, expenses may be reduced.Total airflow rate into the intake manifold at engine idle and low loadconditions may be controlled in a simpler manner by adjusting theposition of the throttle plate such that the amount of air flowingthrough a interior passage of the throttle plate may be controlled, toregulate an amount of vacuum generated at a constricted portion of theinterior passage. Thus, an extra aspirator shut off valve to controlaspirator flow rate into the intake may be avoided enabling a furthersavings in costs. Further a technical effect of increasing an amount ofvacuum generated at a throttle plate, and therefore an amount of airdrawn from a vacuum consumptions device coupled to the throttle platemay be increased by including a hollow interior passage in the throttleplate. The shape, size, and position of the interior passage in thethrottle plate may be adjusted without changing any other component ofthe throttle plate or engine intake. As such, the size and shape of theinterior passage may be adjusted to increase the amount of vacuumgenerated by the interior passage.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory. The specific routinesdescribed herein may represent one or more of any number of processingstrategies such as event-driven, interrupt-driven, multi-tasking,multi-threading, and the like. As such, various actions, operations,and/or functions illustrated may be performed in the sequenceillustrated, in parallel, or in some cases omitted. Likewise, the orderof processing is not necessarily required to achieve the features andadvantages of the example embodiments described herein, but is providedfor ease of illustration and description. One or more of the illustratedactions, operations and/or functions may be repeatedly performeddepending on the particular strategy being used. Further, the describedactions, operations and/or functions may graphically represent code tobe programmed into non-transitory memory of the computer readablestorage medium in the engine control system.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,1-4, 1-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and non-obvious combinationsand sub-combinations of the various systems and configurations, andother features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

The invention claimed is:
 1. A method for an engine, comprising:adjusting a position of a throttle plate with a hollow central passage;and generating vacuum at a constricted portion of the central passage,via intake airflow through the central passage of the throttle plate. 2.The method of claim 1, further comprising, applying the generated vacuumto a vacuum consumption device fluidly coupled to the constrictedportion of the central passage via a hollow shaft, the vacuumconsumption device including a brake booster.
 3. The method of claim 2,further comprising, during the applying of generated vacuum, flowing airfrom the vacuum consumption device through the hollow central passage ofthe throttle plate into the intake airflow through the central passage.4. The method of claim 3, wherein the adjusting is based on a vacuumdemand of the vacuum consumption device, the adjusting including movingthe throttle plate towards a more closed position as the vacuum demandof the vacuum consumption device increases.
 5. The method of claim 4,further comprising adjusting an engine operating parameter responsive toone or more of the adjusting the position of the throttle plate and theflowing air from the vacuum consumption device to maintain engine torqueoutput.
 6. The method of claim 5, wherein the operating parameterincludes boost pressure, and wherein the adjusting includes increasingboost pressure as the throttle plate is moved towards the more closedposition.
 7. The method of claim 6, wherein increasing boost pressureincludes reducing an opening of a wastegate coupled across an exhaustturbine.
 8. The method of claim 5, wherein the operating parameterincludes exhaust gas recirculation (EGR), and wherein the adjustingincludes decreasing a rate of EGR as the throttle plate is moved towardsthe more closed position.
 9. The method of claim 5, wherein theoperating parameter comprises intake valve timing, and wherein theadjusting includes increasing a duration of intake valve opening as thethrottle plate is moved towards a more closed position.
 10. The methodof claim 3, further comprising, adjusting one or more of a fuelinjection amount and fuel injection timing based on each of the intakeairflow through the central passage and the air flowing from the vacuumconsumption device through the constricted portion of the centralpassage into the intake airflow through the central passage to maintainengine combustion at or around stoichiometry.
 11. A system comprising:an engine including an intake conduit; a throttle plate mounted on ahollow shaft positioned in the intake conduit, the throttle plate havinga hollow interior passage extending from an upstream surface to adownstream surface of the throttle plate, for flowing intake air throughthe throttle plate; and a controller with computer-readable instructionsstored in non-transitory memory for: in response to vacuum demand,adjusting a position of the throttle plate to generate vacuum at aconstricted portion of the interior passage as intake air flows throughthe interior passage.
 12. The system of claim 11, further comprising avacuum consumption device, wherein the hollow shaft of the throttleplate is fluidly coupled to the vacuum consumption device and theconstricted portion of the interior passage, where the hollow shaftextends radially outward from the constricted portion of the interiorpassage through the throttle plate, and through the intake conduit alongan axis of rotation of the throttle plate, and wherein the controllerincludes further instructions for applying the generated vacuum to thevacuum consumption device.
 13. The system of claim 12, wherein theadjusting is in response to the vacuum demand of the vacuum consumptiondevice, the controller configured to move the throttle plate towards amore closed position where the intake airflow through the interiorpassage increases to increase vacuum generation at the throttle plate asthe vacuum demand of the vacuum consumption device increases.
 14. Thesystem of claim 11, wherein the interior passage is narrowest at theconstricted portion, whereby a venturi effect is created at theconstricted portion of the interior passage.
 15. The system of claim 12,wherein the hollow shaft comprises a first portion that extends radiallyinward from exterior the throttle plate and is fluidly coupled to afirst side of the constricted portion of the interior passage via afirst opening, and a second portion that is fluidly coupled to a secondside of the constricted portion of the interior passage via a secondopening, the second side directly opposite the first side, and where thesecond portion extends from the second side radially outward into thethrottle plate so that a portion of gasses in the interior passage flowinto the second portion and back into the interior passage.
 16. A methodfor an engine, comprising: connecting a vacuum consumption device via ahollow shaft to a throttle plate positioned in an engine intake passage,the throttle plate having a hollow interior passage; and decreasing anopening of the throttle plate when the vacuum consumption device demandsvacuum to increase vacuum production at a constricted portion of thehollow interior passage.
 17. The method of claim 15, wherein the vacuumconsumption device is one of a brake booster, a fuel vapor canister, anda vacuum actuated valve.
 18. The method of claim 16, further comprisingincreasing boost pressure responsive to the decreasing to maintain anengine torque output, the boost pressure increased by increasing aclosing of a wastegate coupled across an exhaust turbine via anelectronic controller.
 19. The method of claim 16, further comprisingreducing flow of exhaust residuals from an engine exhaust to the intakepassage in response to decreasing the opening of the throttle plate tomaintain an engine torque output.
 20. The method of claim 16, furthercomprising, adjusting one or more of a fuel injection amount and a fuelinjection timing responsive to the decreasing to maintain enginecombustion at stoichiometry.